//
// Created by spiro on 19-3-12.
//

#include <stdio.h>
#include <math.h>
// #define NDEBUG
#include <assert.h>

int main(void) {
    double x, y, z;
    puts("Enter a pair of numbers (0 0 to quit):");
    while (scanf("%lf%lf", &x, &y) == 2
            && (x != 0 || y != 0)) {
        z = x * x - y * y;
        assert(z >= 0);
        printf("answer is %f\n", sqrt(z));
        puts("Next pair of numbers: ");
    }
    puts("Done!");
}